i suppose technically anything was possible. They could have continued with Apollo and established a permanent base. They could have restarted Gemini. They could have done any number of things. The issues were political, not technical.
The idea of a reusable “space truck” caught on with the politicians and, I suppose, the public, so that’s how it went. That was probably not the best choice technically or scientifically, but that’s how it went, and we were stuck with low Earth orbit for decades.